Inductor and method of manufacture



7 W C A E E .vR 7 N. 7 C n w W D E E. C. RECHEL INDUCTOR AND METHOD OF MANUFACTURE Filed March 15, 1965 Oct. 4, 1966 United States Patent 3,277,417 INDUCTOR AND METHOD OF MANUFACTURE Edwin C. Rechel, 85 Lancaster Road, Shirley, Mass. Filed Mar. 15, 1965, Ser. No. 439,632 4 Claims. (Cl. 336192) This invention relates to an inductor and a method of manufacturing the same, and, more particularly, to an inductor characterized by a novel lead-in connection.

Literally millions of coils are used in electronic gear each year. These, in many instances, must be inexpensively produced, and for this purpose a standard procedure is to use a cylindrical or rectangular paperboard form upon which the inductance-providing windings are placed, in many instances thousands of turns. There is no difficulty in making a connection to the outer end of the winding, but there is diflioulty in making a connection to the inner end of the multiple turn winding. In the past, this has required the services of the production people to fish for the inner end of the winding. It will be appreciated that where the wire making up the winding is relatively thin, this can result in rupture and in some instances loss of the entire inductor through mutilation.

Because of the relatively low cost of inductors, it has been the procedure to gang wind a long circular or rectangular tube at spaced-apart points so as to provide a plurality of inductors on a given stick, which may be of the order of 2-3 feet. Thereafter, the stick is severed between the spaced windings to provide 1020 separate inductors. This complicates the matter of providing an easily manipulated lead-in connection.

Both of these problems are solved by the instant invention, and it is therefore a generalized object of the invention to provide an inductor and a method of manufacturing the same which makes simple and straightforward the establishment of the interior lead-in connection.

Other objects and advantages of the invention may :be seen in details of construction and operation set forth in this specification.

The invention is explained in conjunction with an illustrative embodiment in the accompanying drawing, in which- FIG. 1 is a perspective view of a coil form or support which corresponds to a portion of the stick previously referred to and in which certain slits are provided for ultimately establishing the novel lead-in con nections;

FIG. 2 is another perspective view of a coil form or stick in which an elongated conductor has been threaded I through the previously referred-to slits;

FIG. 3 is another perspective view of the coil formthis in a subsequent stage of manufacture wherein windings have been applied;

FIG. 4 is a perspective view of the coil'form of FIG. 3 after the same has been severed into discrete inductors; and

FIG. 5 is a perspective view of a completed inductor and which shows the position of the novel lead-in connection.

It is believed that a description of the process of manufacture embodying the five steps illustrated in the drawing will acquaint those skilled in the art most expeditiously with the invention.

Slitting Initially, a tubular form or support such as that seen in FIG. 1 is equipped with pairs of transverse slits as at 11 and 12, 11' and 12' relative to the tubular form generally designated 10. Here, it will be appreciated that the coil form may assume forms other than cylindrical. For example, many forms are made in rectangular or square cross section. The slits 11 and 12, 11' and 12' are arranged in pairs and are spaced longitudinally, i.e., axially, of the form 10, corresponding to the length of the ultimate inductors developed therefrom. In the illustration given and for .purposes of simplicity, the form 10 ultimately is used to provide two inductors as shown in FIG. 4 and which are designated by the numerals 13 and 13.

Threading The next step following the slitting is to introduce an elongated conductor as at 14 into the interior 10a of the tubular form 10. The conductor 14 is passed through each pair of slits 11 and 12, 11' and 12 to provide an exterior portion as at 15 and 15'.

Winding Thereafter, the form or support 10 is wound (usually in the gang fashion mentioned above) to provide windings 16 and 16. Initially the wire is soldered to the spots 15 and 15. This operation is well known to those skilled in the art, and the windings each may comprehend as many as 30,000 turns, suitably interleaved with insulating paper.

Severing In FIG. 4, the form 10 is seen to have been severed as indicated by the arrow 17, thereby providing the inductors 13 and 13'. These correspond to the windings 16 and 16'. Not shown :but a common practice in this art is to provide an overlying strip so as to confine the outer end of the wire constituting the m ulti-turn winding. It will be appreciated that there is no difficulty in establishing a connection with the outer end of the windingthe problem being with establishing a connection with the inner end of the Winding.

Extraction of lead-in connection Reference is now made to FIG. 5, and it will be noted that in that view the conductor 14 has been reversely folded on itself as at 14a in the vicinity of the slit 11. The slits 11 and 12 are positioned adjacent one end of the inductor 13 so that there is a substantial portion of the conductor 14 which can be folded axially outwardly of the conductor 13 and establish a steady lead-in connection. It will be appreciated that the exposed portion 14 (see FIG. 2) underlies a portion of the initial winding so that there is a good electrical connection established with the winding 16. Advantageously, the conductor 14 may be copper or tin strip to yield the desired flexibility for folding as at 14a.

A wide variety of materials may be employed for fabricating the support 10, it only being necessary that the material of construction be adapted to slitting and threading as represented by FIGS. 1 and 2. The extraction operation indicated in FIG. 5 is readily accomplished by inserting a tool such as that conventionally used for lead finishing in this art-here, the large axial opening of the conductor 13 permits easy manipulation of the tool for the extraction of the lead-in conductoreven by the unskilled artisan.

While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of illustration, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. An inductor, comprising a tubular support, a pair of spaced slits in said support extending generally perpendicularly to the axis thereof, a flexible conductor in said support and extending through said slits and thereby having a portion lying outwardly of the support, a

. a winding on said support in contact with said conductor portion, said conductor having a portion extending axially outwardly of said support to provide a lead-in connection to .said winding.

2. The inductor of claim 1 in which said conductor has a length generally coextensive with the length of said support, said conductor being folded on itself adjacent one of said slits to provide said axially outwardly extending portion.

3. 'In a method of inductor manufacture, the steps of transversely slitting an elongated tube at a plurality of pairs of longitudinally spaced points, threading an elongated conductor through said slits to provide longitudinally spaced conductor portions exteriorly of said tube, winding said tube to provide an inductor, severing said tube between pairs of slits, and folding said conductor on itself to provide a lead-in connection.

4. The method of claim 3 in which said severing is performed relative to each pair of slits so as to position the exterior conductor portion adjacent to but spaced from one end of the inductor developed by said severing.

No references cited.

LEWIS H. MYERS, Primary Examiner. 

1. AN INDUCTOR, COMPRISING A TUBULAR SUPPORT, A PAIR OF SPACED SLITS IN SAID SUPPORT EXTENDING GENERALLY PERPENDICULARLY TO THE AXIS THEREOF, A FLEXIBLE CONDUCTOR IN SAID SUPPORT AND EXTENDING THROUGH SAID SLITS AND THEREBY HAVING A PORTION LYING OUTWARDLY OF THE SUPPORT, A WINDING ON SAID SUPPORT IN CONTACT WITH SAID CONDUCTOR PORTION, SAID CONDUCTOR HAVING A PORTION EXTENDING AXIALLY OUTWARDLY OF SAID SUPPORT TO PROVIDE A LEAD-IN CONNECTION TO SAID WINDING. 